This invention relates in general to transfer assembly for use for example in an electrostatographic reproduction apparatus, and more specifically to a roller transfer assembly which is readily movable to an operative or inoperative position within the reproduction apparatus.
In modern high speed/high quality electrostatographic reproduction apparatus (copier/duplicators or printers), a latent image charge pattern is formed on a uniformly charged dielectric support member. Pigmented marking particles are attracted to the latent image charge pattern to develop such image on the support. The dielectric support is then brought into contact with a receiver member and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric support. After transfer, the receiver member bearing the transferred image is transported away from the dielectric support and the image is fixed to the receiver member by heat and/or pressure to form a permanent reproduction thereon.
Application of the electric field to effect marking particle transfer is generally accomplished by ion emission from a corona charger onto the receiver member while in contact with the dielectric support, or by an electrically biased roller urging the receiver member against the dielectric support. Roller transfer apparatus offer certain advantages over corona transfer apparatus in that the roller transfer apparatus substantially eliminate defects in the transferred image due to paper cockle or marking particle flakes. This result stems from the fact that the pressure of the roller urging the receiver member against the dielectric support is remarkedly efficient in providing intimate uniform contact therebetween. However, roller transfer apparatus are more complex than corona transfer apparatus in that they require cleaning due to their tendency to pick up marking particles from the dielectric support and undesirably deposit such particles on the back side of the receiver member. Further, the roller transfer apparatus, including their cleaning assemblies must be constructed so as not to interfere with ready clearance of any jammed receiver members.